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Test Procedures
Output Voltage Tolerance
Apply the nominal rated DC input to the converter under test.
While drawing the rated load current measure the output voltage of the converter under test.
The tolerance is the difference between the measured voltage (Vout) and the specified
output voltage (Vnom) expressed as a percentage of Vnom:(|Vout-Vnom|/Vnom)*100%.
Line Regulation
Apply the nominal rated DC input to the converter under test.
While drawing the rated load current measure the output voltage of the converter under test. (Vnom)
Apply the minimum rated DC input to the converter under test.
While drawing the rated load current measure the output voltage of the converter under test. (Vlow)
Apply the maximum rated DC input to the converter under test.
While drawing the rated load current measure the output voltage of the converter under test. (Vhigh)
Line regulation is the change in the output voltage as a result of the change in input voltage expressed as (|Vhigh-Vlow|/Vnom)*100%.
Load Regulation
Apply the nominal rated DC input to the converter under test.
While drawing the full rated load current measure the output voltage of the converter under test. (Vfull)
While drawing the minimum rated load current measure the output voltage of the converter under test. (Vmin)
Load regulation is the change in output voltage as a result of the change of output load current expressed as (|Vfull-Vmin|/Vfull)*100%
Ripple and Noise
Apply the nominal rated DC input to the converter under test.
Apply the full rated load current to the output of the converter under test.
To measure the True RMS value connect an AC coupled True RMS voltmeter to the output.
To measure the peak-peak value connect an ac coupled oscilloscope to the output.(be sure to properly decouple the scope probe to insure an accurate measurement.)
Efficiency
Apply the nominal rated DC input to the converter under test. (Vin)
Apply the full rated load current to the output of the converter under test.
Measure the input current to the converter under test. (Iin)
Calculate the input power (Pinput) to the converter expressed as Vin*Iin
Measure the output voltage of the converter under test.
Calculate the output power (Pout) being drawn from the converter under test expressed as Vout*Iout.
Efficiency is ratio of output power to input power expressed as Pout/Pinput.
Semiconductor Circuits, Inc. 14C Industrial Way, Atkinson, New Hampshire, USA 03811